Let's test / on ZFS and /boot on ZFS in separate tests since the GRUB integration for ZFS seems to be not very well maintained.
If the test breaks in the future it's easier to figure out that ZFS on /boot is at fault and either fix the issue or disable the test.
The new test creates a ZFS pool where all features not compatible with GRUB2 are disabled. The dataset is then mounted on /boot and we check that the installer correctly generates a bootable configuration.
Try to use as many ZFS features as possible to verify that GRUB can handle them.
swraid support will now only be enabled by default if stateVersion is
older than 23.11. nixos-generate-config will now generate explicit
config for enabling support if needed.
